Ca2+ plays a critical role in intracellular signaling. Intracellular Ca2+ levels are tightly controlled by continuos removal of Ca2+ via ATP-driven Ca2+ pump in the endoplasmic reticulum and plasma membrane, and the Na+/Ca2+ exchangers (NCX), in the plasma membrane. NCX can move Ca2+ either into or out of cells, depending on the net Na+, Ca2+, and K+ gradient across the membrane. In most cells, 3 Na+ are exchanged for 1 Ca2+. Several genes code for the 3 NCX (NCX1, NCX2, and NCX3), and three in the NCKX family (NCKX1, NCKX2, NCKX3). NCX share significant sequence homology (~70%), display 11 TM domains, a large central, intracellular hydrophilic regulatory loop between TM5 and 6, extracellular N-terminus and cytoplasmic C-terminus. The N-terminal signal peptide is cleaved off from the mature exchanger protein.

In vertebrate photoreceptors, some neurons, and certain other cells, 3 K+ are transported in the same direction as Ca2+, with coupling ratio of 4 Na+ to 1 Ca2+ plus 1 K+ by new class of exchangers called NCKX for K+-dependent Na/Ca+2 exchangers. NCKX share the general topology and functional properties of NCX proteins. Rod exchangers also contains a large hydrophilic segment at the its N-terminus that is not found in NCX. NCKX1 (human 1099/1081aa, bovine 1199aa) is expressed in retinal rod cells. NCKX2 (rat 670aa) shares 80% identity with NCKX1. The two hydrophilic loops are also much shorter in NKKX2 than in NCKX1, accounting largely for the difference between the size of the two proteins. NCKX2 is expressed in various regions of the brain (striatum, parietal cortex, cerebellum, hippocampus, and thalamus). A third member of NCKX family, namely NCKX3 (rat 624aa, mouse 595, and human 644/625) has been cloned and characterized. Human NCKX3 is most abundant in the brain (thalamic nuclei, hippocampal CA1 neurons, layer IV of the cerebral cortex). It is also expressed at lower levels in aorta, uterus, and intestine.

Synthetic peptide corresponding to 16aa of human NCKX3, C-terminal, extracellular domain.

~3kD

Suitable for use in ELISA and Antibody Blocking. Not suitable for Western Blot. Other applications not tested.

ELISA: 5-10ug control peptide per 1ug of aff pure IgG or 1ul antiserum Optimal dilutions to be determined by the researcher.

May be stored at 4°C for short-term only. For long-term storage, store at -20°C. Aliquots are stable for at least 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.

Synthetic peptide

Purified

~1mg/ml

Supplied as a lyophilized powder from PBS, 0.05% sodium azide.

This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.